Graeme McDowell edges past Nicolas Colsaerts to reach the last four of World Match Play

McDowell will aim to go one better than last year on the final day in Bulgaria

Graeme McDowell today finally got the better of Nicolas Colsaerts in the Volvo World Match Play Championship, despite a remarkable escape from an unsavoury hazard by the defending champion.

Colsaerts beat McDowell in the final last year and also knocked the Northern Irishman out in the last eight in 2011, but McDowell made it third time lucky with a 2&1 win in the quarter-finals at Thracian Cliffs.

Three up after nine, McDowell seemed set to go further ahead when Colsaerts' drive on the short par-four 10th bounced over a public toilet and into a lateral water hazard.

But, after taking a penalty drop inside the bathroom - bringing new meaning to the phrase 'nearest point of relief' - Colsaerts was then afforded relief from an immovable obstruction, pitched on to the green and holed from 15 feet for par to halve the hole.

Colsaerts could be heard laughing as he pleaded with the referee not to make him drop the ball inside the bathroom on live television, but had to go through the motions and in fact drop it twice as it rolled nearer the hole the first time.

After then placing it on the floor, Colsaerts took relief from an immovable obstruction and a cart path, allowing him to drop it in the rough almost level with the green.

"I was laughing because I was going to look like a clown," Colsaerts said.

"I'm going to make 'A Question of Sport' and I'm sure it's going to make the news, some Belgian dude dropping the ball in a toilet. It's fun to be recognised for stupid stuff like that."

After escaping with his par, Colsaerts got back into the match with a birdie on the 13th - where McDowell was going to drop at least one shot - and by winning the 14th with a par.

However, he missed a birdie putt from seven feet on the 16th to get back on level terms and then hit two clumsy pitches on the par-three 17th to allow McDowell to close out the win.

McDowell, who almost squandered a four-hole lead with six to play before beating Bo Van Pelt on the 18th in the last 16 this morning, said: "I keep giving guys a look in and you don't want to give them too many chances.

"I was looking like going four up on the 10th and Nicolas then literally makes par from the toilet. It's when the Rules of Golf get a bit funny and wacky and people watching will be wondering what's going on, but what a four he made.

"I'm happy to get through and excited to be in the semi-finals. It's a very historic event and a trophy with a lot of legendary names on it. The golden years at Wentworth I remember watching a lot of my heroes win it and I would dearly love to add my name to the list."

"I was laughing because I was going to look like a clown. I'm going to make 'A Question of Sport'," - Nicolas Colsaerts

McDowell will face Brendan Grace in the last four after he beat England's Chris Wood 2&1 in the quarter-finals, while the other semi-final sees another South African, Thomas Aiken, take on Thongchai Jaidee, both men having beaten Ryder Cup star Ian Poulter in the group stages.

McDowell insisted that his energy levels were high despite playing 35 holes today, but Grace and Aiken both admitted to be struggling to cope with the undulating course, despite players being driven in buggies between many of the greens and tees.

"Thirty six holes a day is definitely starting to take its physical toll," said Aiken, who played both his group matches yesterday as one of the eight unseeded players and needed 19 holes to defeat Ireland's Shane Lowry in the last 16.

"I wish I was a little bit fitter, but I think if you can get through the match tomorrow morning you'll be extremely focused for the afternoon."

Grace, who ended Brett Rumford's bid to join Nick Faldo and Seve Ballesteros in winning three European Tour events in a row with a 4&3 win in the last 16, turns 25 on Monday but added: "I have little aches and pains, a little stiff.

"It's been a long day and I can't remember the last time I played 36 holes in a day."